A Kind of Energy-Efficient Clustering Algorithm for Wireless Sensor Networks

To solve the limited energy problem of nodes in the wireless sensor networks (WSN), a rapid Energy-efficient Clustering Algorithm (EECA) has been proposed. In the initialization stage of the system, the deployment region is rapidly divided into multiple clusters, then the node self energy consumption ratio and degree are chosen as the weigh criterion for cluster head selection, consequently the re-election of a cluster head becomes a locally triggered action. Due to the re-election of cluster head node is only proceeded within the cluster, its complexity and computation load has been greatly reduced. The theoretical analysis indicates that the information and time complexity of EECA cluster formation algorithm are O(1), which means the algorithm has nothing to do with the network size n and has a small cost. Simulation results indicate that EECA can provide better load-balancing performance and less protocol overhead of cluster head nodes. Comparing with LEACH protocol, EECA can reduce the energy consumption and prolong the network lifetime

Field test on the biodegradation of poly(butylene adipate-co-terephthalate) based mulch films in soil

The use of plastic much films has been fundamental to promoting food production in many regions of the world. However, concern is growing about the progressive accumulation of plastic residues in soil after crop harvest and its subsequent impact on soil health and potential to enter the food chain. Although biodegradable films have been developed to prevent these problems, it is still unclear whether they are environmentally benign. Here we evaluated the physical and chemical breakdown of four commercial poly(butylene adipate-co-terephthalate) based biodegradable mulch films (BMF1, BMF2, BMF3 and BMF4) in an agricultural soil over a 26-month period. Based on visual examination, degradation followed the series BMF4 > BMF1, BMF2 > BMF3. Importantly, microplastic residues (fragments <5 mm) still remained in the soil of all 4 plastic types after 2 years, suggesting that they are likely to accumulate over time if used on an annual basis. Viscosimetry, Fourier transform infrared (FTIR) spectroscopy and Thermogravimetric Analysis (TGA) were used to characterise the breakdown process. Our results indicated that the degradation of the mulch film after burial in agricultural soil may be linked to the nature of the polymer but also to its manufacturing formulation. Although the peak changes of polyester in the infrared spectrum were not distinct, the plastic films showed other signs of degradation including a reduction in intrinsic viscosity after burial in soil. The different degradation rates of BMF1 and BMF2 at the molecular level may be due to the different CaCO3 contents. In conclusion, under field conditions, we show that slight variations in the formulations of commercial biodegradable mulch films leads to very different persistence rates in soil. Further, we conclude that their slow rate of degradation will ultimately lead to their progressive accumulation in soil if used repeatedly

Design and Modeling for 2D Plate Type MR Damper

A two-dimensional magnetorheological damper is developed for the engineering two-dimensional damping need. The velocity and pressure distribution model of the two-dimensional plate-type damper, and the damping force calculation model are established based on the Navier-Stokes equation. Several structural and physical parameters, including the working gap δ, the length a, and the width a of the middle slide plate, are analyzed theoretically. The damping performance of the two-dimensional plate-type magnetorheological damper was evaluated using a two-dimensional vibration test-bed, with the effect of the excitation current analyzed. The experimental results suggest a significant influence of Coulomb damping force on the damping force of magnetorheological damper when using appropriate magnetorheological fluid. As the excitation current increases, the damping force of magnetorheological damper becomes larger while the system amplitude decreases gradually in both directions, a maximum reduction of 2.5956 times. It's confirmed that the design of the two-dimensional plate-type magnetorheological damper is reasonable

Antibodies to Cartilage Oligomeric Matrix Protein Are Pathogenic in Mice and May Be Clinically Relevant in Rheumatoid Arthritis

Objective. Cartilage oligomeric matrix protein (COMP) is an autoantigen in rheumatoid arthritis (RA) and experimental models of arthritis. This study was undertaken to investigate the structure, function, and relevance of anti-COMP antibodies. Methods. We investigated the pathogenicity of monoclonal anti-COMP antibodies in mice using passive transfer experiments, and we explored the interaction of anti-COMP antibodies with cartilage using immunohistochemical staining. The interaction of the monoclonal antibody 15A11 in complex with its specific COMP epitope P6 was determined by x-ray crystallography. An enzyme-linked immunosorbent assay and a surface plasma resonance technique were used to study the modulation of calcium ion binding to 15A11. The clinical relevance and value of serum IgG specific to the COMP P6 epitope and its citrullinated variants were evaluated in a large Swedish cohort of RA patients. Results. The murine monoclonal anti-COMP antibody 15A11 induced arthritis in naive mice. The crystal structure of the 15A11-P6 complex explained how the antibody could bind to COMP, which can be modulated by calcium ions. Moreover, serum IgG specific to the COMP P6 peptide and its citrullinated variants was detectable at significantly higher levels in RA patients compared to healthy controls and correlated with a higher disease activity score. Conclusion. Our findings provide the structural basis for binding a pathogenic anti-COMP antibody to cartilage. The recognized epitope can be citrullinated, and levels of antibodies to this epitope are elevated in RA patients and correlate with higher disease activity, implicating a pathogenic role of anti-COMP antibodies in a subset of RA patients.</p

A memória da luz : customizações e encontros com o espectador

Tese (doutorado)—Universidade de Brasília, Instituto de Artes, Departamento de Artes Visuais, 2017.O presente trabalho fala do desenvolvimento e aplicação de simulacros computacionais da luz como opção poética que é estética e empiricamente investigada de modo a envolver a comparação de minhas percepções e meus horizontes, como artista, com os de meus espectadores, como forma de encontrar aproximações e distâncias entre essas percepções e horizontes enquanto criações necessariamente implicadas na fruição esteticamente qualificada desses simulacros, em favor de um maior entendimento sobre o que poderia ser um encontro ou comunicação possível entre autor e receptor e na expectativa de obter, pelo somatório de percepções e horizontes colhidos desses espectadores, uma revelação paulatina das propostas artísticas correspondentes a esses simulacros.This work is about the development and application of computer light simulacra as poetic option that is aesthetically and empirically investigated in a way that involves the comparison of my perceptions and horizons, as an artist, with those of my spectators, as a way to find the proximities and distances between those perceptions and horizons as creations necessarily implied in the fruition aesthetically qualified of these simulacra, in favor of a greater understanding of what could be a possible encounter or communication between author and receiver and in the expectation of a gradual revelation of the artistic proposals corresponding to these simulacra, by the sum of perceptions and horizons taken from those spectators

Pilotirani težnostni podporni zid: deformacijsko-napetostna analiza

The piled retaining wall is a new type of railway retaining structure in China. In the current design, the retaining wall, the beam and the piles are assumed to be independent components. Both the mutual action of the retaining wall, the piles and beam, and the influence of the soil or rock foundation on the structure are not fully considered, so that there are some limitations in the current design method. In this paper, using field observations and a three-dimensional finite-element analysis, the lateral earth pressure on the wall back, the stress distributions and the forces of the reinforcements in the beam and the pile were studied. The simulation results were in good agreement with the field observation data. These results revealed that the tensile stresses were very small and that these stresses were positive in most zones in the beam and the pile. It can also be observed that the tensile stresses or forces in the beam and pile obtained in this study were much smaller than those obtained using the current design method. This clarified the fact that the current design method used for the beam and the pile was very conservative and that it should be optimized to consider the effect of the foundation on the whole structure and the interactions among the different components.Pilotirani podporni zid predstavlja nov tip podpornih konstrukcij na železnicah na Kitajskem. V sedanji praksi projektiranja so podporni zid, greda in piloti obravnavani kot neodvisne komponente. Tako ni obravnavano vzajemno delovanje podpornega zidu, pilotov in grede ter ni popolnoma obravnavan vpliv zemljine ali hribine na konstrukcijo, kar predstavlja določene omejitve v veljavni metodi projektiranja. V članku je podana študija bočnih zemeljskih pritiskov na steno zidu, razporeditev napetosti ter sil v armaturi grede in pilotov, ki uporablja rezultate terenskih opazovanj in tridimenzionalnih analiz na osnovi končnih elementov. Rezultati simulacij se dobro ujemajo z rezultati terenskih meritev. Ti rezultati so pokazali, da so bile natezne napetosti zelo majhne in, da so bile napetosti v večina conah v gredi in pilotih natezne. Prav tako smo ugotovili, da so natezne napetosti ali sile v gredi in pilotu v tej študiji bile veliko manjše od nateznih napetosti dobljenih z veljavno metodo projektiranja. Razjasnili smo, da je veljavna metoda projektiranja za dimenzioniranje grede in pilotov zelo konzervativna in, da jo je potrebno optimizirati z obravnavanjem vpliva temelja na celotno konstrukcijo ter upoštevanjem interakcije vseh komponent, ki sestavljajo sistem

Spatiotemporal variation of drought characteristics in the Huang- Huai-Hai Plain, China under the climate change scenario

peer reviewedUnderstanding the potential drought characteristics under climate change is essential for reducing vulnerability and establishing adaptation strategies, especially in the Huang-Huai-Hai Plain (3H Plain) which is the grain production base in China. In this paper, the variation of drought characteristics including drought event frequency, duration, severity and intensity for the past 50 years (1961-2010) and future scenarios (2010-2099) based on observed meteorological data and RCP 8.5 projections were investigated, respectively. Firstly, the applicability of three climatic drought indices including the Standardized Precipitation Index (SPI), the Standardized Precipitation Evapotranspiration Index based on the Penman–Monteith equation (SPEI-PM) and the Thornthwaite equation (SPEI-TH) were compared in tracing recorded agricultural drought areas. Then, the drought characteristics including drought event, duration, severity and intensity using “run theory” was analyzed for both historical observations and future RCP 8.5 scenarios based on the proper index. Correlation analysis between drought indexes and agricultural drought areas showed that SPEI-PM performed better than SPI and SPEI-TH in the 3H Plain. Based on the results of SPEI-PM, droughts over the past 50 years have experienced reduced drought with shorter durations, and weaker severity and intensity. However, for the future RCP 8.5 scenario, drought is predicted to rise in frequency, duration, severity and intensity from 2010-2099 although drought components during the 2010-2039 were milder compared to historical conditions. This study highlights that the estimations for atmospheric evaporative demand would bring in differences in long term drought trend of drought indexes and consequently the applicability in 3H Plain. The results of this paper can help inform researchers and local policy makers to establish drought risk management strategies

Mechanism and Modeling of Contaminant Accumulation on Hot-Film Air Flow Sensor

Hot-film air flow sensors are now widely applied in many industrial fields. Their accuracy can be seriously affected when there are contaminants accumulated on the sensor chip. To predict the decrease of accuracy caused by contamination, the accumulation mechanism of contaminant particles on the surface of the sensor chip is studied in this paper. The adsorption process of particle is analyzed and a theoretical model of the cumulative thickness of the particles over time is established. A test platform for the particle accumulation is built and a long-term cumulative test is conducted. According to the tests, cumulative thickness of the particles increases while the growth rate slows over time. The results of the test fit those of the theoretical model. Various factors affecting the accumulation of contaminants are analyzed. The results indicate that the cumulative thickness of the particles increases along with the increase of the particle concentration, the particle charge, and the electric field strength on the chip surface but decreases along with the increase of the particle radius. The test results also show that the electrical force is the dominant reason of particle adsorption accumulation. By decreasing the electric field strength on the sensor surface, the cumulative thickness of the particles can be effectively reduced

Modification of Type B Inclusions by Calcium Treatment in High-Carbon Hard-Wire Steel

To investigate the modification of type B inclusions in high-carbon hard-wire steel with Ca treatment, Si-Ca alloy was added to high-carbon hard-steel, and the composition, morphology, size, quantity, and distribution of inclusions were observed. The samples were investigated by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). The experimental thermal results showed that the modification effect of inclusion was better in high-carbon hard-wire steel with Al of 0.0053% and Ca of 0.0029% than that in steel with Al of 0.011% and Ca of 0.0052%, in which the inclusions were mainly spherical semi-liquid and liquid CA2, CA, and C12A7. The inclusion size decreased from 3.2 μm to 2.1 μm. The degree of inclusions segregation was reduced in high-carbon hard-wire steels after calcium treatment. The results indicate that the modification of inclusions is conducive to obtaining dispersed inclusions with fine size. The ratio of length to width decreased and tended to be 1 with the increase in CaO content in the inclusion. When the content of CaO was higher than 30%, the aspect ratio was in the range of 1 to 1.2. The relationship between the activity of aluminum and calcium and the inclusions type at equilibrium in high-carbon hard-wire steel was estimated using classical thermodynamics. The calculated results were consistent with the experimental results. The thermodynamic software Factsage was used to analyze the effect of aluminum and calcium additions on the type and quality of inclusions in high-carbon hard-wire steels. The modification law and mechanism of type B inclusions in high-carbon hard-wire steels are discussed